Add some compile-fail tests

Author: jonas-schievink

cortex-m-rt/tests/compile-fail/non-static-resource.rs

@@ -0,0 +1,43 @@
+//! Tests that no `&'static mut` to static mutable resources can be obtained, which would be
+//! unsound.
+//!
+//! Regression test for https://github.com/rust-embedded/cortex-m-rt/issues/212
+
+#![no_std]
+#![no_main]
+
+extern crate cortex_m;
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception, interrupt, ExceptionFrame};
+
+#[allow(non_camel_case_types)]
+enum interrupt {
+    UART0,
+}
+
+#[exception]
+fn SVCall() {
+    static mut STAT: u8 = 0;
+
+    let _stat: &'static mut u8 = STAT; //~ ERROR explicit lifetime required in the type of `STAT`
+}
+
+#[interrupt]
+fn UART0() {
+    static mut STAT: u8 = 0;
+
+    let _stat: &'static mut u8 = STAT; //~ ERROR explicit lifetime required in the type of `STAT`
+}
+
+#[entry]
+fn you_died_of_dis_entry() -> ! {
+    static mut STAT: u8 = 0;
+
+    // Allowed. This is sound for the entry point since it is only ever called once, and it makes
+    // resources far more useful.
+    let _stat: &'static mut u8 = STAT;
+
+    loop {}
+}

cortex-m-rt/tests/compile-fail/unsafe-init-static.rs

@@ -0,0 +1,45 @@
+//! Makes sure that the expansion of the attributes doesn't put the resource initializer in an
+//! implicit `unsafe` block.
+
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception, interrupt};
+
+#[allow(non_camel_case_types)]
+enum interrupt {
+    UART0,
+}
+
+const unsafe fn init() -> u32 { 0 }
+
+#[entry]
+fn foo() -> ! {
+    static mut X: u32 = init();  //~ ERROR requires unsafe
+
+    loop {}
+}
+
+#[exception]
+fn SVCall() {
+    static mut X: u32 = init();  //~ ERROR requires unsafe
+}
+
+#[exception]
+fn DefaultHandler(_irq: i16) {
+    static mut X: u32 = init();  //~ ERROR requires unsafe
+}
+
+#[exception]
+fn HardFault(_frame: &cortex_m_rt::ExceptionFrame) -> ! {
+    static mut X: u32 = init();  //~ ERROR requires unsafe
+    loop {}
+}
+
+#[interrupt]
+fn UART0() {
+    static mut X: u32 = init();  //~ ERROR requires unsafe
+}